BACKGROUND & AIMS Caspase recruitment domain 9 (CARD9) is an adaptor protein that integrates signals downstream of pattern recognition receptors. CARD9 has been associated with autoinflammatory disorders, and loss-of-function mutations have been associated with chronic mucocutaneous candidiasis, but the role of CARD9 in intestinal inflammation is unknown. We characterized the role of Card9 in mucosal immune responses to intestinal epithelial injury and infection. METHODS We induced intestinal inflammation in Card9-null mice by administration of dextran sulfate sodium (DSS) or Citrobacter rodentium. We analyzed body weight, assessed inflammation by histology, and measured levels of cytokines and chemokines using quantitative reverse-transcription polymerase chain reaction and enzyme-linked immunosorbent assay. Cell populations were compared between wild-type and Card9-null mice by flow cytometry analysis. RESULTS Colon tissues and mesenteric lymph nodes of Card9-null mice had reduced levels of interleukin (IL)-6, interferon-γ, and T-helper (Th)17 cytokines after administration of DSS, compared with wild-type mice. IL-17A and IL-22 expression were reduced in the recovery phase after DSS administration, coincident with decreased expression of antimicrobial peptides and the chemokine (C-C motif) ligand 20 (Ccl20). Although Card9-null mice had more intestinal fungi based on 18S analysis, their Th17 responses remained defective even when an antifungal agent was administered throughout DSS exposure. Moreover, Card9-null mice had impaired immune responses to C rodentium, characterized by decreased levels of colonic IL-6, IL-17A, IL-22, and regenerating islet-derived 3 gamma (RegIIIγ), as well as fewer IL-22—producing innate lymphoid cells (ILCs) in colon lamina propria. CONCLUSIONS The adaptor protein CARD9 coordinates Th17- and innate lymphoid cell-mediated intestinal immune responses after epithelial injury in mice.

The identification of transcriptional regulatory networks, which control tissuespecific development and function, is of central importance to the understanding of lymphocyte biology. To decipher transcriptional networks in T-cell development and differentiation we developed a browsable expression atlas and applied a novel quantitative method to define gene sets most specific to each of the represented cell subsets and tissues. Using this system, body atlas size datasets can be used to examine gene enrichment profiles from a cell/tissue perspective rather than gene perspective, thereby identifying highly enriched genes within a cell type, which are often key to cellular differentiation and function. A systems analysis of transcriptional regulators within T cells during different phases of development and differentiation resulted in the identification of known key regulators and uncharacterized coexpressed regulators. ZBTB25, a BTB-POZ family transcription factor, was identified as a highly T cell-enriched transcription factor. We provide evidence that ZBTB25 functions as a negative regulator of nuclear factor of activated T cells (NF-AT) activation, such that RNA interference mediated knockdown resulted in enhanced activation of target genes. Together, these findings suggest a novel mechanism for NF-AT mediated gene expression and the compendium of expression data provides a quantitative platform to drive exploration of gene expression across a wide range of cell/tissue types. (Blood. 2010;115(26):5376-5384) IntroductionT cells undergo thymic development and differentiate into distinct subsets defined by cytokine production and effector functions. This development depends upon Notch and Wnt signaling pathways and transcription factors including GATA3, MYB, RUNX1, IKZF1, and TCF7 (for review see Rothenberg et al 1 and Singer et al 2 ). In contrast to B cells, where PAX5 and EBF1 were identified as B-lineage specific in expression and function, many of the known T-cell regulators are not restricted to the T lineage. 1 In addition, several factors that have critical roles in T-cell development, such as, MYB, GFI1, STAT5B, TOX, and POU2F1 are stably expressed throughout development. 3 These observations lead several investigators to hypothesize that T lineage-specific factors remain to be discovered, and several studies have attempted to identify these novel Transcription factors (TFs). [4][5][6] However, these studies focused on changes between different T-cell subsets or between T cells and a few limited numbers of non-T-cell controls. Given that transcriptional steady state abundance is best quantified with respect to other cells, we hypothesized that T cell-specific factors will emerge only in an extensive dataset that includes a large number of immune and nonimmune cells and tissues.We compiled a large dataset of 557 publicly available microarrays that covers 126 normal primary cells/tissues and reveals expression patterns of approximately 12 000 genes. A novel benchmarking system was devised that enhances the s...

Summary CARD9 is a central component of anti-fungal innate immune signaling via C-type lectin receptors, and several immune-related disorders are associated with CARD9 mutations. Here we used a rare CARD9 variant that confers protection against inflammatory bowel disease as an entry point to investigate CARD9 regulation. We showed that the C-terminal truncated CARD9 protective variant acted in a dominant negative manner for CARD9-mediated cytokine production, indicating an important role for the C terminus in CARD9 signaling. We identified TRIM62 as a CARD9 binding partner and showed that TRIM62 facilitated K27-linked poly-ubiquitination of CARD9. We identified K125 as the ubiquitinated residue on CARD9 and demonstrated that this ubiquitination was essential for CARD9 activity. Furthermore, we showed that Trim62-deficient mice have increased susceptibility to fungal infection, similar to Card9-deficient mice. This study utilizes a rare protective allele to uncover a TRIM62-mediated mechanism for regulation of CARD9 activation.